Project Background. Homeless Veterans smoke at an inordinately high rate (80%) compared to the general U.S. population (20%), and thus are at increased risk for the lethal effects of cigarette smoking. Smoking cessation treatment including smoking cessation aids such as nicotine replacement therapy (NRT) are greatly underutilized, particularly among homeless Veteran smokers. There is a special need to develop effective interventions that target homeless Veterans. Homeless Veterans are significantly less likely to access intensive clinic-based smoking cessation care. While the efforts of our group and others have expanded the reach of smoking cessation treatment options beyond the clinic to include tele-medicine, cognitive-behavioral telephone counseling, and internet based interventions, it has been suggested that there is a need for more innovative and intensive approaches to smoking cessation in order to improve quit rates, particularly among homeless Veterans. The use of intensive behavioral therapies, such as contingency management (CM), may be a useful component for smoking cessation interventions among homeless Veterans. CM has shown efficacy for reducing smoking in other difficult-to-treat populations. Project Objectives. The primary goal of the current study is to evaluate the effectiveness of an intervention that combines evidenced-based treatment for smoking cessation with smart-phone based, portable contingency management on smoking rates compared to a VA smoking cessation specialty care intervention in a randomized controlled trial among homeless Veteran smokers. Specifically, 126 Veterans will be randomized to receive Abstinence Reinforcement Therapy (ART) which combines evidenced based cognitive-behavioral telephone counseling, a tele-medicine clinic for access to NRT, and mobile contingency management (mCM), or to receive VA smoking cessation specialty care intervention. The specific aims and hypotheses are: AIM 1: To investigate the impact of ART on rates of abstinence from cigarettes at post-treatment, 3-month and 6- month post-treatment follow-ups. Hypothesis 1: Abstinence rates will be significantly higher among Veterans randomized to the ART-based intervention than those randomized to the VA smoking cessation specialty care control arm. AIM 2: To evaluate the relative cost-effectiveness of the ART intervention. Hypothesis 2: ART based treatment will result in greater cost-effectiveness compared to the control condition as measured by the incremental cost- effectiveness ratio. AIM 3: To assess potential treatment mediators including self-efficacy-related mechanisms. Hypothesis 3: Increased abstinence associated with ART will be partially mediated by increased self-efficacy compared to the VA specialty care control condition. Project Methods and Expected Results. Proposed is a four year project in which 126 homeless Veteran smokers will be randomized to receive either a multi-component Abstinence Reinforcement Therapy or a VA specialty care control intervention. Participating patients will be surveyed at post-treatment, 3-months and 6- months post-randomization. The primary outcome of the trial is prolonged self-reported abstinence at the 6-month follow-up, verified by cotinine assay. It is expected that ART will improve quit rates among homeless Veterans, and compared to specialty care, will be associated with greater cost-effectiveness.